1. Field of the Invention
The present invention relates to a data retrieval or searching system capable of searching stored data for one or more items which comply with one or more specified retrieval conditions of requirements.
2. Description of the Prior Art
The conventional data retrieval systems may in general include a sequential file system in which keywords are sequentially arrayed for binary search, and a random file system in which keywords may be so converted as to permit the random access. In both systems, one or more items complying with one specified retrieval condition or requirement may be retrieved. Therefore indexes for respective items would be required for changing retrieval conditions or requirements. Furthermore it has been very difficult to retrieve one or more items complying with a combination (a logical combination) of retrieval conditions or requirements. Thus the cost of software required is high and the data retrieval speed is low.